论文部分内容阅读
大气氮(N)沉降能够直接或间接影响土壤微生物的生长繁殖和活动能力,改变土壤微生物群落结构及功能,对土壤中物质转化及营养物质有效性产生影响.选取山西太岳山油松林,对油松天然林和人工林土壤微生物量对模拟氮沉降的响应进行了研究.2009年9月开始每月中旬进行氮处理.样地处理分别为对照(CK,0 kg hm-2a-1,以N计,下同)、低氮(LN,50 kg hm-2a-1)、中氮(MN,100 kg hm-2a-1)和高氮(HN,150 kg hm-2a-1).2011年6、8、10三个月,分0-10cm和10-20 cm两个土层采集土壤样本,用氯仿熏蒸法分别测定土壤中微生物生物量碳(MBC)、氮(MBN).结果表明:不同林分的土壤MBC、MBN差异显著(P<0.01),天然林MBC、MBN含量高于人工林.相同氮处理下,0-10 cm土壤微生物量显著高于10-20 cm土层(P<0.01).不同浓度氮添加处理对土壤MBC影响不显著(P>0.05),但是对MBN影响显著(P<0.01).MBC随着季节变化明显(P<0.01),而MBN随季节变化不大(P>0.05).
Atmospheric nitrogen (N) deposition can directly or indirectly affect the growth, reproduction and activity of soil microorganisms, and change the structure and function of soil microbial communities, affecting the material conversion and availability of nutrients in the soil. The responses of soil microbial biomass of natural and artificial forests to simulated nitrogen deposition were studied, and nitrogen treatment was conducted from mid-September to mid-September 2009. The plots were CK (0 kg hm-2a-1, N (LN, 50 kg hm-2a-1), medium nitrogen (MN 100 kg hm-2a-1) and high nitrogen (HN 150 kg hm-2a-1) Soil microbial biomass carbon (MBC) and nitrogen (MBN) were measured by chloroform fumigation method in 6, 8 and 10 months, respectively, in 0-10cm and 10-20cm soil layers.The results showed that: The contents of MBC and MBN in different forest stands were significantly different (P <0.01), while the contents of MBC and MBN in natural forest were higher than those in plantation. Under the same nitrogen treatment, the soil microbial biomass in 0-10 cm layer was significantly higher than that in 10-20 cm layer <0.01) .But the MBC had no significant effect on soil MBC (P> 0.05), but it had a significant effect on MBN (P <0.01) .The MBC changed significantly with the seasons (P <0.01) (P> 0.05).